- Orrill, C. H., Copur-Gencturk, Y., Cohen, A., & Templin, J. (2020). Revisiting purpose and conceptualization in the design of assessments for teachers of mathematics.
*Research in Mathematics Education*.* - Weiland, T., Orrill, C. H., Nagar, G. G., Brown, R. E., & Burke, J. (accepted). Defining and operationalizing a robust understanding of proportional reasoning for teaching.
*Journal of Mathematics Teacher Education*. - Brown, R. E., Weiland, T., & Orrill, C. H. (2019). Mathematics teachers’ use of knowledge resources when identifying proportional situations.
*International Journal of Science and Mathematics Education*. - Williams-Pierce, C., Plaxco, D., Reimer, P. N., Simpson, A., Orrill, C. H., Burke, J. P., Sinclair, N., Guyevskey, V., Ellis, A. B., & Dogan, M. F. (2019). Mathematical play: Across ages, context, and content. In S. Otten, A. G. Candela, Z. de Araujo, C. Haines, & C. Munter (Eds.),
*Proceedings of the forty-first annual meeting of the North American Chapter of the International Group for the Psychology of Mathematics Education*(pp. 1979-1990). St Louis, MO: University of Missouri. - Orrill, C. H., Brown, R. E., Burke, J. P., Epstein, M., & Harper, A. (2019). Quantity: It may not be as easy as it appears. In S. Otten, A. G. Candela, Z. de Araujo, C. Haines, & C. Munter (Eds.),
*Proceedings of the forty-first annual meeting of the North American Chapter of the International Group for the Psychology of Mathematics Education*(pp. 777-778). St Louis, MO: University of Missouri.

This project explores the effectiveness of two different versions of professional development (PD) designed to enhance middle school mathematics teachers’ understanding of fractions and proportions, and their teaching of these mathematical concepts to students. The PD uses an approach that engages teachers with web-based apps that allow them to test and experiment with their mathematical ideas. The apps, combined with guiding questions that challenge teachers’ thinking about fractions and proportions, serve both to promote critical thinking about the concepts and to further developing their understandings of the concepts. The researchers will use an innovative approach, topic modeling, to examine the effectiveness of each of version of the PD.